Koss PortaPro is really a classic product. It has been popular for more than 20 years. Is it not enough to prove its classic level? The main reason is that the bass is powerful enough. Although the boom is not powerful enough, it is still powerful, and is more suitable for rock music and other music. The metal head beam is used to ensure firmness. Although the appearance is quite special, it is still very comfortable to wear. The Koss PortaPro recently has a low price of 24.99 US dollars, about 155 yuan, and the price is about 220 yuan. Taobao generation is a mixture of good and bad people. It's better to be confident of the classic good things.